Acceleration Sensor Cap Section Pad Arrangement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional acceleration sensors experience decreased detection accuracy due to increased offset voltage from parasitic capacitance and susceptibility to extraneous noise, primarily caused by long wire connections between pads and circuit devices.
Innovation Solution
The acceleration sensor design incorporates a cap section with movable and fixed electrode pads arranged on the circuit device side, reducing wire length and parasitic capacitance, and separates these pads to minimize noise interference, utilizing a comb-teeth structure and through-hole electrodes for efficient signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pads are arranged on the sensor section side, then wire length increases, but manufacturing is simpler
Solution Approach 1:
The pad arrangement utilizes the cap section's outer surface, transitioning from a planar arrangement to a three-dimensional configuration that leverages the cap's depth. This allows pads to be positioned optimally for short wire connections while maintaining manufacturing feasibility through standardized cap molding processes.
Solution Approach 2:
The electrode pads are segmented into movable electrode pads and fixed electrode pads that are spatially separated and independently arranged on the cap section's outer surface. This segmentation allows each pad type to be optimally positioned relative to the circuit device, minimizing wire length for each connection type independently.
2Reliability
If wire length is reduced, then parasitic capacitance decreases, but pad arrangement becomes more complex
Solution Approach 1:
The cap section integrates multiple functions: it protects the sensor section, provides a mounting surface for electrode pads, and serves as a structural element for wire connections. By merging these functions into a single component, the design achieves short wire lengths without proportionally increasing overall device complexity.
Solution Approach 2:
The electrode pads are pre-positioned on the cap section's outer surface during cap manufacturing, before final assembly with the circuit device. This preliminary arrangement optimizes wire routing paths and minimizes connection length while maintaining manufacturing efficiency through standardized cap production processes.
3Length of moving object
If pads are placed adjacent to each other, then wire length shortens, but noise interference increases
Solution Approach 1:
The movable electrode pads and fixed electrode pads are arranged in an asymmetric configuration on the cap section's outer surface. This asymmetric layout optimizes wire routing to the circuit device while incorporating sufficient spatial separation between electrode types to minimize mutual noise interference, balancing both wire length and noise considerations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively suppresses the increase in offset voltage and noise influence, thereby maintaining or improving detection accuracy and reducing the impact of carrier waves as noise sources.
Implementation Method 1
a sensing section including a movable electrode displaceable in accordance with acceleration and a fixed electrode arranged to face the movable electrode, and outputting a sensor signal corresponding to a capacitance between the movable electrode and the fixed electrode
Data Source
AI summary
An acceleration sensor includes: a sensor section having a cap section; a sensing section including movable and fixed electrodes and movable and fixed electrode connecting sections; a peripheral section. The cap section includes a movable electrode through-hole electrode in a movable electrode through hole and a fixed electrode through-hole electrode in a fixed electrode through hole. The cap section further includes a movable electrode pad connected to the movable electrode through-hole electrode and a circuit device and a fixed electrode pad connected to the fixed electrode through-hole electrode and the circuit device. The movable electrode pad and the fixed electrode pad are adjacent to each other in a region of the cap section overlapped with the peripheral section in the stacking direction.